Hepatitis B vaccine: prophylactic, therapeutic, and diagnostic dilemma.

Hepatitis B virus (HBV) remains a serious public health problem worldwide, accounting for high morbidity and mortality rates as well as significant personal, societal, and economic costs. Hepatitis B is a preventable disease; a safe and effective vaccine has been available for 30 years. The World Health Organization aims to control HBV worldwide by integrating HB vaccination into infant, possibly adolescent, and at-risk adult routine immunization programs. In recent years, a drastic reduction in the mortality and morbidity of chronic HBV, including hepatocellular carcinoma, has occurred, particularly in hyperendemic areas. In addition, a therapeutic vaccine that enhances patient immune response has been considered as a possible alternative to antiviral agents. However, mutant HBV may infect individuals who are anti-HBs positive after immunization (vaccine-escape) and/or fail for detection of HBsAg (diagnostic-escape), which may lead to transmission through donated blood or organs. This review attempts to summarize the prophylactic, therapeutic, and diagnostic concerns on HBV vaccines.